Teeth whitening devices generate and supply radical species that act on pigment molecules of teeth to whiten the teeth. For example, medical teeth whitening devices for dentists are known. The medical teeth whitening devices irradiate oxygen-based bleach with ultraviolet rays or heats oxygen-based bleach to generate radical species from the oxygen-based bleach. The ultraviolet irradiation or heating is performed while supplying the oxygen-based bleach to the oral cavity. Accordingly, peroxide included in the oxygen-based bleach may touch the teeth or gums, or the teeth or gums may be irradiated with or heated by the ultraviolet rays, and this may cause damage to the teeth or gums.
Home teeth whitening devices that generate radical species without using oxygen-based bleach in view of such influence on the teeth or gums are known. PTL 1 discloses an example of such home teeth whitening devices.
A teeth whitening device according to PTL 1 includes a gas cylinder that stores gas to form plasma, and a plasma generating cell that generates plasma including radical species as active ingredients from the gas in the gas cylinder. The teeth whitening device according to PTL 1 further includes an applicator tube with a plasma outlet, and a hose that couples the plasma generating cell with the applicator tube.
A user of the teeth whitening device drives the plasma generating cell while holding the applicator tube in such a manner that the plasma outlet is directed toward a whitening target tooth. The plasma generated by the plasma generating cell is supplied to the tooth through the applicator tube.
According to PTL 1, the user is required to keep the position of his or her hand not to move the plasma outlet of the applicator tube off the whitening target tooth while using the teeth whitening device. In view of this, the teeth whitening device according to PTL 1 has room for improvement for usability.